A drive circuit is described in German Patent Application No. DE 198 41 270 A1 for generating a constant current through at least one light-emitting diode. The drive circuit contains a circuit system for generating a voltage which differs from a specified supply voltage and which is applied to the light-emitting diodes to be operated. A current flowing through the light-emitting diodes is detected by a current detector. The voltage present at the output of the circuit system is selected as a function of the magnitude of the current flowing through the light-emitting diodes.